To establish smooth comfortableness for a passenger by decreasing unstable motions in the operation originating from the minimum idling current.

A dual magnet controller 10 as an active roller guide(ARG) controller includes actuators 18a and 18b which are under control, and therein it is required at least to generate a minimum idling current rather than to carry minimum idling current. The controller 10 for special control shaft decides a force command for actuator to constitute a pair based upon the actuators 18a and 18b which generate the net force, and each actuator generates a force of a size at least equal to the specified minimum idling force. The net force is calculated by other material of the ARG controller and is supplied as input to the dual magnet controller.